The invention relates to a method and apparatus for controlling a yarn false twist texturing machine of the type disclosed in WO 98/033963 and corresponding U.S. Pat. No. 6,209,302.
Texturing machines of this kind comprise a plurality of processing stationsxe2x80x94normally as many as 216 or more processing stationsxe2x80x94which are arranged side by side on one longitudinal side of the machine. Each of the processing stations comprises a plurality of processing units for respectively advancing, texturing, drawing, and winding a yarn to a package. The processing units and, thus, the process steps in the individual processing stations are monitored and controlled via a central machine control unit. For the operation, the control unit normally comprises an operator controllable visual display unit, which permits visualizing and changing control and monitoring data. However, it is also common to use two separate visual display units respectively for controlling and monitoring the process. To be able to intervene in processing steps, a plurality of process controllers are provided, which are all connected to the central machine control unit. It is possible to connect the process controllers to the processing units in two ways. As disclosed in WO 98/033963, it is possible to operate the processing units within a processing station by individual drives with associated controllers, so that a plurality of process controllers are associated to each processing station. In this instance, all process controllers connect to a central machine control unit.
In a second variant, which is disclosed, for example, in DE 33 24 243, processing units of the same function in all processing stations are operated by a central drive, so that all processing units of the same function can be controlled by one process controller. In this variant, the expenditure for the control system is considerably reduced in comparison with the foregoing variant with individual drives, however, with the disadvantage that all processing stations of the texturing machine must be operated synchronously.
It is therefore an object of the invention to provide a method of controlling a texturing machine for false twist texturing a plurality of synthetic filament yarns in a corresponding plurality of processing stations as well as such a texturing machine, wherein a high flexibility is accomplished in the processing of the yarns with a simultaneously little expenditure for the control system.
The invention is based on the fact that the texturing machine is divided into a plurality of sections, with each of the sections being controlled independently. Thus, a texturing machine with, for example, a total of 216 processing stations is divided, for example, into a total of 18 sections. With that, each of the sections would comprise 12 processing stations. The processing stations of a section are monitored and controlled independently of the processing stations of adjacent sections. The special advantage of the invention lies in that it is possible to produce with one texturing machine, yarns with different settings in the sections. Furthermore, it is possible to shut down each of the sections independently of the adjacent sections for maintenance and elimination of defects, thereby minimizing a production loss. A further advantage is to be seen in that all sections are jointly supplied from one feed line of supply voltage to the texturing machine. To this extent, it is especially advantageous to connect the sections jointly to a main switch or an emergency switch.
To be able to perform within the section on all processing stations substantially the same process steps, an advantageous further development of the method according to the invention provides for monitoring and controlling all process steps of the section by means of a field control unit associated to the section. To this end, all process-relevant parameters are stored in the field control unit. Likewise, the operating data from the processing stations are continuously supplied to the field control unit. Thus, the field control unit permits an individual monitoring and control of the section.
One advantageous embodiment of the method of the invention provides for individually controlling each process step of one of the processing stations independently of the other process steps of the processing station. In particular, this variant of the method permits operating the process units employed as feed systems in a simple manner at different advancing speeds. Thus, it will be advantageous, when all feed systems have the same advancing speed while threading a yarn in a processing station. Only after the yarn is threaded, will the advancing speeds be made different, which leads to a drawing of the yarn.
A particularly great flexibility in processing the individual yarns within a section of the machine is accomplished by a variant of the method wherein the process steps of a processing station are individually controlled irrespective of the process steps of adjacent processing stations.
However, there is also the possibility of controlling as a group the process steps of adjacent processing stationsxe2x80x94in particular those of the same functionxe2x80x94independently of the other process steps of the processing station. Thus, for example, for unwinding the yarns from a feed yarn package, it is possible to jointly activate the first feed systems of a section.
A further development of the method according to the invention is especially suited for operating the different kinds of process steps within a processing station with the least possible control resources. In this instance, the intended processing steps include, for example, advancing, heating, drawing, twisting, and winding. Thus, it would be possible to control with advantage the process steps as a group, which are performed for advancing the yarn. Contrary thereto, it is preferred to individually control the process steps for twisting a yarn.
In the case that process steps of a plurality of processing stations of a section are combined to a group, a further development of the method is especially advantageous for enabling a shutdown of the process steps independently of the control. Such a shutdown becomes necessary, for example, in the case of a yarn break within a processing station, or when a continuously monitored parameter within a processing station is exceeded.
The method of the present invention is based on a texturing machine with a very large number of processing stations, so that within a section at least six yarns, preferably at least twelve yarns are simultaneously processed in parallel, side-by-side relationship.
The texturing machine of the present invention represents the solution to the underlying object in terms of an apparatus. To this end, the plurality of processing stations are divided into a plurality of sections, each section comprising a plurality of processing stations. Associated to each section is one of several field control units for controlling and monitoring the processing stations of the section. The process controllers for controlling the processing units of the processing stations of a section connect to their associated field control unit. Each section with its associated field control unit thus forms a partial machine, which is to be operated individually. In this connection, the process parameters are predetermined by the field control unit.
To operate the texturing machine, the field control units connect independently of one another to a microprocessor, so that an operator is able to display the data of one of more field control units, or to input or change data on an operator-controllable visual display unit.
To increase the efficiency of a texturing machine, it is further proposed to adapt the microprocessor for being coupled via a line data network to a diagnosis station, thereby enabling a fast intervention by a central station upon occurrence of a defect.
To transmit data between the field control unit and the process controllers, as well as between the process controllers and the field control unit, it is advantageous to provide a serial bus system. With that, it is possible to quickly perform adjustment changes.
Based on different requirements of individual process steps, the amount and frequency of the data exchange between the processing units and the field control unit are different. To this end, the bus system may advantageously consist of a plurality of data networks, which have different data transmission rates.
To be able to make individual adjustment changes in the process steps of the processing stations, an advantageous further development of the texturing machine according to the invention provides for associating an individual one of the process controllers to each of the processing units of the processing stations pertaining to one section.
Within the processing stations, which contain no major changes, the process steps may advantageously be realized by dividing the processing units of the processing stations of a section into groups of the same function, and an individual process controller is associated to each group of processing units.
To maintain the flexibility in the processing of yarns despite combining individual process steps of adjacent processing stations to groups, a further development of the texturing machine provide for associating a switch to at least one portion of the processing units, by which the processing units are switchably connected to one of the process controllers, the switch being activatable independently of the process controller.
However, such a texturing machine is also suited by itself for solving the problem underlying the present invention. As a result of activating the processing units in groups, the switchable connection between the processing units and the process controllers permits individually activating with advantage each of the processing stations. For example, when a yarn lap occurs in one feed system of a group of jointly controlled feed systems, it will be possible to shut down the affected feed system by the process controller, without influencing the adjacent feed systems in their activation.
The switches provided between the processing units and the process controllers may advantageously be activated by the overriding field control unit.
However, it is also possible to associate to the processing units a monitoring unit, which activates the switches in a case of need.
To be able to shut down a processing unit quickly and without major delay, when need arises, an advantageous further development provides for a sensor arrangement for monitoring at least one parameter of the processing unit. The sensor arrangement connects to the monitoring unit associated to the processing unit or to the field control unit associated to the processing unit. For example, it is possible to select as parameters the temperature of a motor, which a temperature sensor measures directly on the motor, or a desired rotational speed of a drive, which a speed sensor measures directly on a drive. However, it is also possible to trigger the shutdown directly by a signal of the field control unit or monitoring unit, which occurs as a result of a signal from a yarn detector.
Advantageously, the control functions and the monitoring functions are performed by an operator from an operator-controllable visual display unit, the latter being connected to the microprocessor. However, it is also possible to perform the control functions and the monitoring functions from two separate visual display units.
According to a preferred further development of the invention, the sections include each at least six processing stations, preferably twelve processing stations.